Comparable front end sales increase 1.6% from January 2011. Walgreens had January sales of $5.80 billion, a decrease of 2.3% from $5.93 billion for the same month in fiscal 2011. Total front-end sales increased 2.7% in January 2012 compared with the same month in 2011, while comparable store front-end sales increased 1.6%, following a 0.6%…